Solution of the Einstein–Maxwell equations with anisotropic negative pressure as a potential model of a dark energy star

Bibi, Rashida; Ферозе, Тооба; Siddiqui, Adil Masood

doi:10.1139/cjp-2016-0069

Cited by 16 publications

(16 citation statements)

References 31 publications

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“…For a solution of the field equations to be physically acceptable [10,48,49], they must satisfy in the following conditions: for which the metric is given by (27) through the boundary r=R where M is the total mass of the star. < 0 (29) and according to the equations (28) and (29) the energy density and radial pressure decrease from the centre to the surface of the star.…”

Section: Physical Acceptability Conditionsmentioning

confidence: 99%

Strange Stars Models in the Color-Flavor Locked State<strong> </strong>

Malaver¹,

Kasmaei²

2019

Preprint

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In this paper, we found new classes of exact models to the Einstein-Maxwell system of equations which describe the internal structure of a compact star made of strange matter considering the equation of state proposed by Rocha, Bernardo, de Avellar and Horvath in 2019. It has been assumed that this matter is composed of equal number of up, down and strange quarks and a small amount of electrons required to reaching the charge neutrality. If this hypothesis is correct, the neutron stars could be strange stars or hybrid stars with a thin crust of nuclei where the temperatures and pressures are capable of converting hadronic matter into this new stable phase of quarks. We have chosen a particular form of gravitational potential Z(x) that depends on an adjustable parameter related to degree of anisotropy of the models and the new solutions can be written in terms of elementary and polynomial functions. The obtained models satisfy all physical features expected in a realistic star and the expressions for mass, density and stellar radius are comparable with the experimental results.

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Section: Physical Acceptability Conditionsmentioning

confidence: 99%

Strange Stars Models in the Color-Flavor Locked State<strong> </strong>

Malaver¹,

Kasmaei²

2019

Preprint

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“…Evidence of this expansion has been shown independently from measurements of supernovae of type Ia and from microwave background radiation [2]. It is proposed that this cosmological behavior is caused by a hypothetical dark energy, a cosmic fluid parameterized by an equation of state ω = p/ρ < -1 /3 where p is the spatially homogeneous pressure and ρ the dark energy density [1][2][3][4]. The dark energy possesses a strong negative pressure that can help to explain the acceleration of the universe in expansion [4].…”

Section: Introductionmentioning

confidence: 98%

“…It is proposed that this cosmological behavior is caused by a hypothetical dark energy, a cosmic fluid parameterized by an equation of state ω = p/ρ < -1 /3 where p is the spatially homogeneous pressure and ρ the dark energy density [1][2][3][4]. The dark energy possesses a strong negative pressure that can help to explain the acceleration of the universe in expansion [4]. The range for which ω < -1 has been denoted phantom energy and possesses peculiar properties, such as negative temperatures and the energy density increases to infinity in a finite time, resulting in a big rip [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…The dark energy possesses a strong negative pressure that can help to explain the acceleration of the universe in expansion [4]. The range for which ω < -1 has been denoted phantom energy and possesses peculiar properties, such as negative temperatures and the energy density increases to infinity in a finite time, resulting in a big rip [2][3][4]. It also provides a natural scenario for the existence of exotic geometries s uch as wormholes [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Malaver and Esculpi [16] presented a new model of dark energy star by imposing specific choice for the mass function which correspond an increase in energy density inside of the star. Bibi et al [4] obtained a new class of solutions of the Einstein-Maxwell field equations which represents a model for dark energy stars with the equation of state p r =-ρ.…”

Section: Introductionmentioning

confidence: 99%

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New Models of Dark Energy Stars with Charge Distributions

Malaver¹,

Esculpi²,

Govender³

2019

IJASS

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In this paper, we have obtained a relativistic and spherically symmetric stellar configuration that describes an anisotropic fluid with a charge distribution that represents a potential model for a dark energy star and we specify particular forms in the gravitational potential and the electric field intensity which allows solve the Einstein-Maxwell field equations. The reason for proposing this model originates from the evidence that recent observational findings suggest that the universe has an accelerated cosmic expansion and the model of dark energy star is one of the most reasonable explanations of this phenomena. The field equations are integrated analytical and new stellar configurations are obtained are analyzed. For each these solutions we found that the radial pressure, the anisotropy factor, energy density, metric coefficients, mass function, charge density are regular and well behaved in the stellar interior. With the new solutions can be developed models of dark energy stars physically acceptable where the causality condition is not satisfied or the strong energy condition is violated. This model has a great application in the study of the fundamental theories of physics and cosmology. Several independent observations indicate that the greater part of the total energy density of the universe is in the form of dark energy and the rest in the form of nonbaryonic cold dark matter particles, but which have never been detected.

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Cosmological solutions with charged black holes

2017

Self Cite

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We consider the problem of constructing cosmological solutions of the Einstein-Maxwell equations that contain multiple charged black holes. By considering the field equations as a set of constraint and evolution equations, we construct exact initial data for N charged black holes on a hypersphere. This corresponds to the maximum of expansion of a cosmological solution, and provides sufficient information for a unique evolution. We then consider the specific example of a universe that contains eight charged black holes, and show that the existence of non-zero electric charge reduces the scale of the cosmological region of the space. These solutions generalize the Majumdar-Papapetrou solutions away from the extremal limit of charged black holes, and provide what we believe to be some of the first relativistic calculations of the effects of electric charge on cosmological backreaction.

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Solution of the Einstein–Maxwell equations with anisotropic negative pressure as a potential model of a dark energy star

Cited by 16 publications

References 31 publications

Strange Stars Models in the Color-Flavor Locked State<strong> </strong>

Strange Stars Models in the Color-Flavor Locked State<strong> </strong>

New Models of Dark Energy Stars with Charge Distributions

Cosmological solutions with charged black holes

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